Wrathful Magic, Demonic Sin
by Love-is-Cyanide
Summary: 15 year old Harry Potter is desperate to survive against 70 year old Voldemort, willing to do whatever it takes. Even if "whatever it takes" means drinking Demon's Blood. Too bad no one told him of the consequences. Full summary and warnings inside.


Title: Wrathful Magic, the Demonic Sin

Summary: During the Second Blood War, Harry potter realized that, as a 17 year old boy destined to kill, or be killed by, a 70 year old semi-immortal tyrant, he was no where near powerful enough to survive. He dove into research, desperate for anything to help him, eventually coming across a possible solution; Demon Blood.

It really is a pity that he didn't look at the consequences. After all, dealing with demons has a high price, and blood has the highest price of all…

Warnings: Violence, War, Death, mental trauma, demon dealings, murder, all that fun shit, groping, AU after 5th year, mentions of abuse, slow updates.

AN: Alright. This little baby is based off of the anime, with any extra info coming from the SDS Wiki. As always, let me know if you see anything wrong. Hopefully, this won't be a complete fuck up like my HPxKHR crossover Skull de Mort: Stuntman, Arcobaleno, Wizard.

Disclaimer: I don't own Harry Potter or Seven Deadly Sins. If you see anything recognizable but unaccredited, PM me ASAP so I can fix it. Please support the official owners.

Prologue:

Harry Potter had had many life changing moments, more than the average child.

Orphaned at 15 months, learning that he had a name at 5 years, learning he was a wizard at 11 years, gaining his first friends that same year, meeting his parents' murderer again that year, discovering he was a parselmouth at 12, discovering he had a Godfather at 13 years, becoming the Hogwarts Tri-Wizard Champion at 14 years, but this one really took the cake.

He didn't know whether to laugh or cry. According to a prophecy created by the blind drunk that lived in the top of the North Tower, he had to kill a 70-year-old seemingly immortal tyrant, or die. He was 15 years old, and had just led a group of teenagers to the Ministry of Magic's Department of Mysteries to save a Godfather that had later been killed by his cousin Bellatrix LeStrange.

He was a 15-year-old boy, destined to defeat a 70-year-old insane wizard who'd been trying to kill him since he was a babe.

He was an untrained 15-year-old boy, going against one of the most powerful Dark Lords to terrorise the British magical community in history.

He was a child, being told that he was to play War with the adults, and expected to survive.

 _He wasn't strong enough._

And Dumbledore just sat there, twinkle absent from his eyes as he watched Harry Potter, the Boy-Who-Lived, _The Chosen One_ , break down as he delivered the terrible news, not offering support, not offering training.

Just watching, like he always did.

~~~OOO~~~

Once Harry had calmed down, exhausted from his uncontrolled magic that had thoroughly trashed the Headmaster's office, he slumped into the overstuffed chair that had conveniently appeared behind him, and waited.

What he waited for, he didn't know. Maybe he wanted assurances from the elderly wizard across from him. Maybe he wanted an offer of training. But no such thing was offered, just sad blue eye and a cracked voice repeating "I'm sorry my boy. I'm sorry."

He sat there for 30 minutes, hoping for something. When that something never came, he stood up, and walked out of the room. Silent, empty, and numb.

~~~OOO~~~

Telling his friends about the prophecy was probably one of the hardest things he had to do.

Telling them that he had to become a murderer, or be slaughtered.

Telling them made it _real_ , made him accept that this was his life, that he was _Fate's Bitch_.

Seeing the sympathy, _the pity_ in their eyes was awful.

Ron saying that this meant they had to stop being friends, Hermione agreeing with him, with so much worse.

He didn't know what to do, what to say to that, so he just nodded solemnly, and left them in the hospital wing, holding back the tears that were trying to fall.

~~~OOO~~~

There was one week left of term. One week before he went back to Hell, before he returned to Number 4, Privet Drive.

One week to start training. To start researching a way to defeat Lord Voldemort, You-Know-Who, the Dark Lord, He-Who-Must-Not-Be-Named.

He spent the entire week in the library, only leaving to eat, use the toilet, and when Madame Pince dragged him by his ears because "The library closed 4 hours ago, Potter, and I'd like to get some sleep tonight!"

The end of term feast was the worst one yet, and everyone noticed.

The whole school noticed that Harry Potter, local celebrity, was sitting alone at the end of the Gryffindor table, dark bags under his eyes, barely eating. The Slytherins were happy, the Ravenclaws puzzled, the Hufflepuffs worried, because what was so bad that it ended the Golden Trio?

~~~OOO~~~

The summer holidays were his most productive. He couldn't do anything related to magic, so he began working on his physical health, gaining strength, speed and stamina.

Every morning and evening he'd go for a jog to the local park, do as many push ups and sit ups as he could, then jog back home. It was exhausting work, but by the end of the holidays, he could sprint where he used to jog, and do one handed push ups.

The Dursleys didn't know how to react to his sudden exercise regime, but didn't comment beyond "Make sure all you chores are done, and if you're home late, you're sleeping outside."

Shockingly, sometimes Dudley would join him while running. They didn't say anything, or even acknowledge that the other was there, but Harry did appreciate his silent companion, and hoped that it was maybe a sign that his overweight cousin was, _finally,_ becoming a better person.

~~~OOO~~~

Dumbledore dropping him off at the Burrow for the final week of summer was incredibly awkward. Ron and Hermione were there, and refused to talk to him beyond the obligatory "Morning Harry" at breakfast. When Mrs. Weasley pulled all three aside one afternoon and asked what the big deal was, Harry revealed that he had been told the prophecy, and Ron and Hermione's decision to end their friendship.

Later that night, he overheard the Weasleys having a family meeting about what the prophecy could mean for them, and their conclusion, as a family, to distance themselves from him.

~~~OOO~~~

Everyone noticed when Harry Potter sat alone at the Opening Feast. They noticed the regretful and worried looks his dorm mates were shooting him, but they also noticed that no one moved to talk to him, to sit with him.

The Slytherins that followed Voldemort were pleased, but everyone else was worried. What did it mean for them, that their supposed Hero, their Destined Saviour, had been abandoned by his friends.

~~~OOO~~~

He quit the quidditch team, and when McGonagall tried to tell him that he had a duty as the new Captain, told her quite firmly that "I have an insane Dark Lord after my head. I don't have time to play quidditch, Professor. Find someone else to do it."

He threw himself back into his research, combing the library, and once he gained the note from Slughorn, the restriced section, greedily absorbing the words contained in the books.

In classes, he was distracted, yet focused. He would work towards that day's objective until he had completed it, and then immediately dig out a random heavy tome from his bag and begin reading, ignoring all calls from the teacher to rejoin the class. The massive loss of points and many detentions, which he didn't attend, only served to further ostracise him from his year mates, but he was desperate for a way to survive the coming war, and nothing was going to stop him.

Dumbledore made numerous attempts to have Harry go to his office, but he refused every time. He was still furious with the old man and his insistent belief in only telling people what they need to know.

Finally, 3 weeks after the Christmas holidays, he found a possible clue.

Buried deep within one the oldest tomes in the restricted section, only a page's worth, was his possibly only chance of survival.

It was evil, it was dark. It would be life changing, and irreversible. It would earn him a dementor's kiss if the Ministry found out, and an Azkaban sentence if they found out he even _knew_ about it.

It was Demon's Blood.

It was his only hope.

~~~OOO~~~

AN: So, what do you think? Almost no dialogue, and pretty dramatic prologue, but does it work?


End file.
